Grinding machine



' Jan. 2, 1940. 5 (jRQMpTQN J 2,185,837

GRINDING MACHINE Filed March 16, 1938 5 Sheets-Sheet 1 Dnvcntor Jan. 2, 1940. G. CROMPTON, JR

GRINDING MACHINE Filed March 16, 1938 5 Sheets-Sheet 2 Jan. 2, 1940. e. CROM'PTON. JR

GRINDING MACHINE 5 Sheets-Sheet 5 Filed March 16, 1938 QQN ARR Q9. hmw

1940- G. CROMPTON, JR 2,185,837

GRINDING M CHINE Filed March 16, 1938 5 Sheets-Sheet 5 3nventor Patented Jan. 2,1940

PATENT OFFICE GRINIiING mcnmn George Crompton, Jr., Worcester, Mm, assignmto Norton Company Worcester, Mass a 001'? poration of Massachusetts Application March 16,

7. Claims.

The invention relates to grinding machines, and with regard to its more specific features to grinding machines adapted to grind a plurality of cams on a camshaft.

l One object of the invention is to provide an improved cam grinding machine, for grinding the cams of automotive camshafts, whereby a slight taper may be ground on each' cam and adjustmehts and changes made without procuring a new 10 set of master cams. Another object of the invention is to provide a readily adjustable automatic grinding machine of the type indicated. Another object of the invention is to provide readily controlled apparatus for dressing a grinding wheel for ll the production of a plurality of tapers on a given work piece of the same dimensions without readjusting the cross slide ofthe machine. Another object of the invention is to provide a simple and accurate mechanism for dressing a grinding wheel 20 to a frusto-conical shape. Another object of the invention is to provide an automatic machine for the grinding of automotive camshafts to tapered surfaces. Other objects will be in part obvious or in part pointed out hereinafter.

25 The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to behereinafter described, and the scope of the application of which will be indiao cated in the following claims.

In the accompanying drawings in which is shown one of many possible embodiments of the mechanical features of this invention,

Figure 1 is a front elevation of a grinding machine to which the invention may be applied;

Figure 2 is a rear elevation of the grinding machine, illustrating certain features of the invention;

Figure 3 is a fragmentary cross sectional view of the cross slide, wheel head and feed screw;

Figure 4 is a vertical sectional view through the table or carriage of the grinding machine, illustrating certain controls;

Figure 5 is a fragmentary elevation of some of 45 the controls-on the front of the machine;

Figure 6 is a view, partlyin rear elevation and partly in section, of the wheel head-cross slide construction and the fluid pressure mechanism to move the former angularly on the latter;

Figure 7=is a fluid pressure diagram.

For convenience, so far as the parts are the same, I have adopted the same numerals for the several parts as are used in Letters Patent No. 2,022,178.

I! As conducive to a clearer understanding of the 1938, Serial No. 196,235 (on. 51-101) present invention, it is noted that the illustrative embodiment discloses it as an improvement of the hydraulically operated automatic cam grinding machine of U. S. Letters Patent No. 2,022,178 granted November 26, 1935 on application of Albert G. Belden and Herbert A. Silven. The 7 machine of that patent has a work table or carriage upon which is mounted a rock bar upon which the work piece is held by centers, the rock bar being rocked back and forth by the engagement of a master cam roller, which is stationary in the direction of oscillation, with one of the master cams which are mounted upon the rock bar. The grinding wheel is mounted upon the usualcross slide, the spindle of the grinding wheel being journalled in the upper part of the cross slide, sometimes referred to as the wheel head, and there being no provision for movement or adjustment between the wheel head and the cross slide. In fact, these have usually been considered the same part and have been often made as an integral casting. I

In the' machine of the patent referred to, the table or carriage is automatically moved from station to station for the grinding of the several "cams on the automotive product camshaft and, at the completion of a grinding operation, or between rough grinding and finish grinding, the

wheel is automatically dressed by a dressing device which consists of a holder secured to the carriage presenting a diamond for contact with the wheel by relative motion of the carriage and wheel. I I V .The dressing apparatus of said patent has certain highly desirablecharacteristics which I wish to maintain unimpaired. The dressing tool holder is a somewhat'massive'casting rigidly secured to the work table or carriage which in turn weighs several tons and moves on the main ways of the base. There is thus little chance for vibration or any play or undesired movement of the dressing diamond during the dressing operation.-

In the automobile engine as now manufactured,

the camshaft is a steel forging, allthe cams being 5 integral with the shaft. The cams lift the valves by engagement with tappet the bottoms of which have the shape of 'disks and may beof hardened steel. Nevertheless it is found that there is a tendency of the cam to wear a groove in the bottom of the tappet rod. which eventually interferes with the .adiustment of the valves.

Accordingly, automotive engineers have recently adopted the improved feature of forming each of the cams with a slight taper which causes the cams to revolve the tappet rods or the disks. thus distributing the wear.

If automotive camshafts are to be formed with a slight taper, the grinding machine which automatically grinds them should form them with this shape, as subsequent to flush grinding there is usually only a polishing operation, if any operation, further performed upon the cams. Camshafts with a slight taper have been made on automatic grinding machines of the type disclosed in the aforesaid Patent No. 2,022,178 by providing master cams of different size, decreasing in size from one end of the master camshaft to the other end thereof, and also mounting the rock bar on the table or carriage non-parallel to the ways 5 thereof. This, it will be seen, produces the desired taper camshaft with. all the'cams on the product shaft of the same size because the dis-' turbance of the relation between the forward pomachine of the type disclosed in said Patent.

2,022,178 is in itself an operation requiring considerable care. The product cams will be no more accurate than the master cams which form them. It has been customary to shape a plurality of identical master cams and to key them to the master camshaft in varying angular positions, as required for the operation of the internal combustion engine. The provision of a plurality of these master cams, all of different sizes, greatly increases the expense of operation and maintenance of the machine and, furthermore, the chances of error are thereby greatly increased. In fact, it has been difllcult to maintain all the product cams of the same size in accordance with the system just described, in which the master cams are of different size, and it should be noted that tolerances in the grinding of camshafts are fine.

According to the present invention, the machine of the Belden and Silven Patent 2,022,178 or other cam grinding machine is equipped with improved features whereby a single size of master cam may be used and yet the dressing of the wheelmay be effected according to said patent, utilizing the massive table to hold the dressing diamond for the attainment of the most accurate results in forming the wheel.

As illustrated in the drawings, the improved automatic cam grinding machine comprises a base 50 which supports a wheel slide 5| for transverse movement thereon on the V-.ways 52 which in turn rotatably supports a grinding wheel 53. The base also supports a longitudinally movable work supporting table 54 which is arranged to slide on a V-way 55.

Camshaft supporting mechanism A rock bar 58 is joumalled in the bearings 59 and 60 which are rigidly fixed to the table 54 so that bar 58 is free to rock therein. A headstock'Bl and footstock 62 are mounted on the rock bar 58 and are provided with centers to rotatably support a camshaft B3. A master camshaft 64 is supported at one end in the headstock GI and at the otherend in a bearing 65 which is fixed to the rock bar. The master camshaft is provided with a plurality of spaced master cams 66. which correspond with the number of product cams on the camshaft to be ground. A master cam roller 61 is slidahlv mounted on a shaft 68 The master camshaft and product camshafts are preferably rotated by a power drive through universal joints H and I2 and the connecting shaft 73. A motor 14 is preferably provided to rotate these parts through a clutch member together with suitable gearing which need not be herein described.

Automatic indexing master camrolrer The master cam roller 61 is preferably indexed automatically so as to position it in operative relation with successive master cams on the master camshaft to conform with the cams being ground on the product camshaft. This mechanism, as illustrated in the drawings, is substantially the same as that illustrated in the prior patent to C. G. Trefethen et al. -No. 1,783,755 dated December 2, 1930. Since this feature does not constitute the subject matter of the claims, it has been illustrated only in outline, as shown in Fig. 2. For further disclosure as to details of this construction, reference may be had to the above-mentioned patent. A dog bar is fixed by a bracket 96 to the base of the machine.

The other end of the dog bar 95 is slidably supported in brackets 91 and 98 which are carried by the table 54. The dog bar 95 is provided with a plurality of adjustable dogs 99 engaged by a star wheel 100. By suitable gearing including gear I03 the star wheel I08 shifts a rack bar I05. The rack bar I05 is slidably mounted in the brackets 69 and I0 and is connected to move the master cam roller 61 in an endwise direction. It will be readily appreciated from the foregoing disclosure that when the table 54 is traversed,

longitudinally, the star Wheel will engage the dogs 99 successively which in turn, through the gearing will move the rack bar I85 and index the master cam roller 61 automatically into alignment with the master cam corresponding to the product cam.

Rock bar actuation The rock bar 58 is normally held under a yieldable tension so that a master cam 66 is held in operative contact with the master cam roller 61. This tensioning device is similar to that shown in the prior patent above mentioned and preferably comprises a cylinder H0 pivotally' supported on the bracket 70. A piston III is slidably mounted within the cylinder H0 and is connected by a piston rod H2 with an arm H8 which is fixedly mounted to the rock bar 58. A spring H4 is interposed between the piston Ill and a collar H5 in the base of the cylinder H0. The spring H4 is a compression spring of sumcient strength to hold the master cam 66 in.

proper contact with the master cam roller 51 during the rotation of the master cam and the rocking of the bar 58.

A fluid pressure mechanism is provided to rock the bar 58 to an inoperative position automatically before the table is traversed so that the master cam and follower and product cams and r dit swh wi l 1,. r ene a e t tee eitrar er's neei -i ab e is St rted-..T 1smcha sm fiu m s u nd r Us Mendly m e b s ths 5 i i f 'q electiw e-p st ed- I rr n d to contact with a projection. I2I of the arm I I 3. h efleisiend pre v 'n li mitted t t c lin rs fl Pis n H9 eves w d yv and rocks ,the proJectionIZI and thearmI I3 torock 10 the bar 58 and separate the master cam' 66 from the follower rbllen iil (Fig. '7). fluid-.under pressurefis,.preferablyladmitted to the cylinder H8 in a, definite timed relation. to the action of th he v me han sm f m ne a,

"Grinding wheel drive mechanism The grindihg wheel may be driven from any suitable sourcel of power, such as a am driving motor"IZ5 Inountedjeither on. the; base of the 20 machineorfori the floor adjacent to l b l-base, as illustratedfin the drawings. The motoris con+ nected by'a p'lllleyfl26 and a belt I21 td'a. pulley 12s on the, jack 'shaft l29 whichfisrotatably sup ported'in bearings I30 and' I3I on the Wheelfhead 25 5111. j Theshaft I29 is providediwith'a uney I32 which is 'onne'cted; byla"belt' I33 to rotate a r en' iwne ed es I Wheel spindle reciprocating mechanis'mp:

30 Thegrinding wheel. is fed bythe straight-in or plunge cut method, It is,therefore deslrable that a su' blemechanism be'providedlto 'recipro cate the gr fdingwheel"axiallyduring the grindn. i I n the ma'chine illustratedin the wheel spindle reciprocating device I35 is utilized Th" "echanism has .notbeen'showri corresponds, with the mechfl ,tl'ie'prior patent to Belden" et.al. t ayra, "1926.1 This" mecha; j comprises a Iw'ormj I36 .v mounted ,wheel jspiridle which inturn 55'" are qm i we, The cylinder. 14 hi is fixed ctthawh nee lfiwnsin p d w apiston I41 connected by a piston rod I48 and link I49 with fixelev eliitltlwi l-b lr adi appreciated from ,this at when fluid is ad- 70 niltted't t willcause a downton' l41 and rock the ction to stop the wheel Fluid under pressure is rfintiined relation with feeding movement of the grinding wheel so that 6: "tii'ebther mechanisms of the Y machine to stop the wheel spindle reciprocation d in ..nth w e;- ofwthetsfl w e a i hereinafterdescribed.

finding wheel jeeding 'mechanism lTheg ri nding wheel-slide 5| is arranged for a feeding movement to control the movement of the grinding wheel toward and from the work. This mechanism.preferablyljcomprises a nut I55 depending from slide 5I a'nd engaging a feed screw 10 I56 which-is rotatably mounted in the bearings I51 and .I58 in the base 500i the machine. A hand'wheel I61 on the front of the machine is connected totum thefe'ed screw I56. 4

ln an automatic machine of this type, it is 15 preferable, to provide-a suitable mechanismfor rapidly moving the grinding wheel to and from a grinding position. As illustrated in the drawings, a fluid pressure mechanism is provided having a cylinder I10-which is formed either as an integralpart of the base or fixedly mounted therein. The rod I1I which is preferably an extension of the feed screw. I56 is aligned with the axis of the cylinder and serves as a piston rod. A piston I12 isslidably mounted within the cylinder I10 and is rotatably supported' on a reduced end portion I13 of the; piston rod I1I. An end thrust bearing I14 is interposed between a shoulder on the rod; I 1I'andone end of the piston I12 and a second end thrust bearing I15 is interposed between the other end of the piston I12 and a sleeve I16 whichsurrounds the portion I13 of the piston rod; I1I. The sleeve I16 is held in proper adjustmentlby means of adjusting nuts I11 on the outer end of the reduced portion I 13. By tightening or loosening the nuts I11, the end thrust of the bearings I14 and I15 may be adjusted. It will bereadily apparent from this construction that when-the piston is moved endwise, it will transmit-,a feeding .movement to the grinding wheel through the rod I1I, feed screw I56, half nut I55, to move the wheel slide 5|. The feed screw is arranged sothat it may be rotated relative to the piston so that the operator, by manual rotation ofthe feed screw, may readily adjust the position of the grinding wheel relative to the fluid pressure mechanism.

In a feeding mechanism of this type, it is desirable that the grinding wheel be fed to a pre When the piston moves forward to feed the grinding wheel into the work, the sleeve I88 contacts with the gauge I81 definitely limiting the forward on successive grinds, the wheel may be brought to the same position.-

A fluid pressure control valve I90 is provided to regulate the admission of fluid to said cylinder. This valve is preferably of the balanced piston type having a valve stem I9I and a plurality of valve pistons I92, I93, I94, and I95 which'are slidably mounted within the valve I90. The ports in the valve are so arranged that fluid from a reservoir I98 is forced by a pump I99 through a conduit 200 into a valve chamber 20I. As the valve stem I9I is shifted from one extreme to the other extreme position, the fluid flow may be changed from one side of the piston I12 to the" shifted to partially cut off the fluid fiow through the valve I90 to the cylinder I10. When the valve I90 is in the position illustrated in Fig. 7, fluid under pressure is forced through a pipe 202 into the cylinder chamber 203 to move the piston I12 toward the right-hand end of the cylinder and thereby cause a rearward movement of the grinding wheel and its supporting slide. During this movement, fluid is exhausted from a cylinder chamber 204, through a pipe 205, a valve chamber-205 and through an exhaust pipe 201 into the reservoir I98.

To obtain a forward feeding movement of the grinding wheel, the valve stem I9I is shifted toward the left, as viewed in Figs. 3 and 7, so that fluid under pressure passes from the valve chamber 20!, through the pipe 205 into the cylinder chamber 204, to move thepiston I12 and the grinding wheel toward the work. During this movement, fluid is exhausted from the cylinder chamber 203, the pipe 202, through a valve chamber 208 and exhaust pipe 291 into the reservoir.

It is. desirable to have a finely adjustable port for regulating the exhaust of fluid from the chamber 203 so as to produce a slow but uniform feed j grinding operation.

of the grinding wheel into the work during the This is preferably accomplished by an actuating means which moves the valve stem I9I so that the valve piston I93 partially covers a V-port I95 connected with the pipe 202 so that fluid thereafter exhausts at a slower but uniform rate to produce the desired grinding feed of the wheel. If desired, the actuating mechanism may be so adjusted that the valve piston I93 entirely covers the v-port I95 so that fluid thereafter exhausts through a pipe 209, a needle valve 2I0, and a pipe 2 into the reservoir I98. By manipulation of the needle valve 2 I 0, the operator may obtain a desired slow grindv ing feed. The actuation of the valve stem I9I to obtain a reversal in direction of the grinding wheel movement is preferably obtained by means of a main control valve which is hereinafter described.

Feed control valve actuating mechanism groove of a collar 22I on the outer end of the valve stem I9I. The rock arm 220 is pivotally mounted on a stud 222 which is supported in brackets 223 on the base of the machine. The am 220 has an inwardly extending arm 224 which carries an adjustable dog 225 which is arranged'in' the path of an adjustable screw 225 on the collar I85 which is "carried by the reduced end portion I13 of the 'piston rod. It is readily. apparent from this disclosure that when the rod I13 is moved in a direction toward the left, as viewed in Figs. 3 and '7 to cause an infeeding movement of the grinding wheel, the valve stem I9I is positioned so that both intake and exhaust ports are wide open to permit a rapid approaching movement of the grinding v.253 by means of a short arm 254.

aromas? wheel toward the work. This movement continues until the adjustable stop screw 225 strikes the upper end or cam face of the dog 225 so as to rock the arms 224 and 220 and move the valve stem I9I so as to partially out 01f the exhaust of fluid to produce a slower but uniform grinding feed of the wheel into the work.

It is desirable to provide a suitable mechanism for shifting the valve stem I9I when the wheel is moving rearwardly to either stop the rearward feeding movement or slow down its movement before the piston I12 engages the end of the cylinder. This is preferably accomplished by means of a collar 240 which serves as a cam to rock a bell crank lever 24I which is mounted on the stud 222 so as to cause a movement of the rock arm 220 and valve stem I9I toward the left. An adjusting screw 242 is located adjacent the outer end of the bell crank lever 24I to permit adjustment of the time when the valve is actuated. A similar adjusting screw 243 is provided at the lower end of the bell crank and is arranged to engage a portion of the rock arm 220 to provide a further adjustment so that the valve stem I9I may be moved a sufficient distance to partially cut off the exhaust of fluid from the pipe 205 or to entirely cut it ofl so as to either slow down or stop the rearward movement of the grinding wheel Table traverse or indexing movement The work supporting table .54 is traversed or indexed longitudinally and automatically by means of a fluid pressure system comprising a cylinder 250 which is fixed to the base of the machine. A piston 25I is slidably mounted within the cylinder 250 and is connected by a piston rod 252 to a bracket 253 depending from the under side of the table 54. The admissionof fluid to either cylinder chamber 254 or 255 is controlled by a valve 255. Fluid from the pump I99 passes through pipe200,a pipe 251 into a valve chamber 258. A pipe 259 is connected between the valve 255 and the cylinder chamber 254 and a pipe 250 is connected between the valve 255 and the cylinder chamber 255. It will be readily ap-' parent from this disclosure that when the valve 255 is in the position illustrated in Fig. 7, no fluid will be admitted to either of the cylinder chambers and the table will remain stationary.

The valve 255 is provided with a valve stem 25I which is operatively connected to a manually operable control lever 252 mounted on a rock shaft The arm 254 is mountedon the rear end of shaft 253 and has a pin engaging a groove on the valve stem 25I. It will be readily apparent from this construction that when the lever 252 is moved in a clockwise direction, the valve stem 25I will be moved toward the left, as viewed in Fig. "I, so as to admit fluid through pipe 259 to the cylinder chamber 254 and cause a movement of the table 54 toward the right (Figs. 1 and 7). Similarly, when the lever 252 is moved in a counterclockwise direction, the valve stem 25I will be moved toward 'the right so as to pass fluid through the pipe 250 into the cylinder chamber 255 to move the table 54 toward the left.

The lever 252 is normally held in the full line position 252a as indicated in Fig. 5 or in the opposite position by means of an arrow point 255 on the lever fixed on the end of the shaft 253 and engaged by a spring pressed roller 255. See Figs. 2 and 7. The lever 252 isin the dotted line position 252D (Fig. 5), while the table is indexed 2,185,887" "of the lever 215. When the lever 282 is moved intermittently in a position toward the left. The lever 262 is in the opposite position, to the right, while the table is being indexed intermittently as it moves toward the right. The valve stem 261 is normally in a position to admit fluid either through the pipe 259 or the pipe 268 to the cylinder 258. The admission of fluid through the pipe 251 to the valve 256 is controlled by a main control valve, as will hereinafter be described.

An actuating mechanism is provided for thevalve so that movement of the work supporting table 54 operates to close the valve 256 so that when the table is traversed a predetermined distance to position the next cam in front of the grinding wheel, the valve is automatically closed to stop the table against further movement. This is preferably accomplished by means of a dog bar 218 which is adjustably mounted on the front edge of the table. The dog bar 218 is provided with a T-slot 211 in which is a plurality of ad-- justable dogs 212. The dogs may be adjusted along the bar 218 to conform with the spacing of the cams on the product camshaft. The dog bar, if necessary for any variation in successive camshafts, may be adjusted longitudinally of the table without upsetting the adjustment of the individual dogs.

There is provided a secondary actuating lever for cooperating with the table dogs. As illustrated in Fig. 4, a dog lever 215 is pivotally mounted on a stud 216. The lower end of the dog lever 215 is provided with a projecting pin 211 which rides in a cylindrical aperture 218 in the lever 262. See Figs. and 7.

Assuming the lever 262 is positioned as illustrated in Fig. 1, that is, in a neutral position, the

lever 262 is thrown either manually or automatically into position 262b to move the valve stem 26! and admit fluid through pipe 268 into cylinderchamber 255 to start the movement of table 54 in a direction toward the left. This movement traverses the camshaft supporting table 54 to bring the first product cam into operative relation with the grinding wheel. The traversing movement continues until the dog lever 215 isto move. the lever either toward the right or tov ward the left. The swinging of the lever 262 from position 2621; into the full line-position, as indicated in Fig. '7, moves the valve stem 26l into the position illustrated in Fig. 7, so as to cut oif fluid pressure from both of the pipes 259 and 268,

thereby stopping the niovementof the.work carrying table. By adjusting the position of the dogs 212 along the dog bar 218, the stopping position of the table may be adjusted as desired so that the product cams will be positioned successively in operative relation with the grinding wheel.

. The vdog lever 215 is slidably mounted on the stud 216 so that it may be thrown out of the path of the dogs 212 to permit a furthertraversing movement of the table. A lever 282 (Figs. 5 and 7) is pivoted on a stud 283 and at its upper end is formed as a yoke having pins 284 and 285 engaging slots 28l in opposite sides of the hub 286 clockwise (Fig. 7), the dog lever 215 is moved rearwardly on the stud 216 out of the path of the dog 212 so as to permit a further traversing or indexing movement of the table. This movement is preferably accomplished in timed relationship with the other operating mechanisms of the machine. A fiuid pressure cylinder 281 is mounted within the machine base and isprovided with a piston 288 having a piston rod 289 engaging an end 298 of the lever.282. A spring 291 which surrounds the piston rod serves to normally retain the piston 288 in its rearward position. Fluid pressure is admitted through a pipe 292 into a cylinder chamber 293 in timed relationship with the other operating mechanism of the machine to rock the lever 282 and thereby slide the dog lever 215 into an inoperative position out of alignment with the dogs 212. This mechanism is preferably controlled by the main control valve, which is hereinafter described, so as to operate automatically in timed relation with the other move- 7 ments of the machine.

Pilot valve opposite side of the axis of the spring pressed mile! 266. This is preferably accomplished by means of a pilot valve 295 which is of a balanced piston type valve and normally held in a neutral or inoperative position by means of a spring 296. When the table reaches its end position in .its movement towards the left, a depending projection on an adjustable truing dog 291 (Figs. 1 and 5) engages the upper end of a pilot valve lever 298 (Figs. 4 and '1) and rocksit so as to move a valve stem 299, so as to admit fluid which enters through a pipe 388 and a valve chamber 38l into a pipe 382 which passes fluid under pressure into a valve chamber 383 at one end of the traverse of the index control valve 256. This pressure moves the valve stem 26l so that the control lever 262 and arrow point 265 pass over the high point on the roller 266 and shifts the valve 256 into a reverse position so that after truing of the grinding wheel, the table '54 is ready for an in termittent traversing or indexing movement in a direction towardthe right, as viewed in Fig. 1.

Wheel truing mechanism In a machine of this type, it is desirable that the wheel be automatically trued so that the grinding .may be accomplishedby a freshly trued wheel face. Referring now tothe right-hand side of Fig. 1, a bracket 385 is fixedly mounted on the table 54' and carries a truing tool 386 which may be adjusted. by a micrometer mechanism 381. After the last cam on the shaft has been ground, the grinding wheel is moved to an extreme rearward position with the piston I12 engaging the rear end of the cylinder (Fig. 3). The table 54 is then given an additional traversing movement to carry the previously adjusted diamond or truing tool 386 across the grinding wheel 53, while it is in its extreme rearward position.

The normal traversing or indexing movement -of the table is comparatively rapid to prevent tions. This table speed is not well suited for a truing operation which requires a very slow, uniform relative traversing movement between the truing tool and the grinding wheel. To attain a slow feeding movement of the table, a suitable slow speed or throttle valve 3 I 0 is provided. When fluid is exhausted from the cylinder 250, through either pipe 259 or 230, it passes through either chamber 3 or 3I2, pipes 3I3 or 3 respectively and then through valve chambers 3I5 or 3I3 in the pilot valve 295 and through a common exhaust pipe 3I1 which enters a valve chamber 3I3 in the slow speed valve 3I0. A V-port 3I9 in the valve chamber 3I3 is connected by a pipe 320 with the reservoir. During the normal traversing or indexing movement of the table, the v-port 3| 9 is wide open, permitting unrestrained exhaust of fluid from the cylinder 253. When the table 54 indexes or traverses from the last cam on the camshaft and moves toward a truing position, a cam 322 (Fig. 1) on the truing dog 291 strikes a roller 323 which is mounted on the upper end of-a spring pressed plunger 324. The lower end of the plunger engages a rock arm 325 mounted on the outer end of'a rock shaft 323. The other 'the shaft 326 and arm 321 and valve stem 328 moves the valve piston 329 toward the right (Fig.

'1) with the V-port 3I9 partially closed, thereby restricting the exhaust of fluid from the cylinder 250 so as to produce a slow traversing movement of the work table and the diamond or truing tool 303 across the operative face of the grinding wheel 53.

At the same time the slow, speed valve moves to throttle the exhaust of fluid to cause a slow truing movement of the table, a pipe 335 is uncovered by movement of a valve piston 333 to admit fluid from a pipe 331 through a valve chamber 333, a pipe 335, into the cylinder chamber I50 to actuate the lever I43 and thereby stop the wheel spindle reciprocation during the truing movement. The table continues its truing movement towards the left until the pilot valve lever 293 engages the truing dog 291 to move the pilot valve from a neutral position and admit fluid under pressure into the chamber 303 of the traverse valve 253 to reverse thedirection of travel of the table. The table moves slowly to pass the diamond across the face of the wheel on its return stroke. The slow movement continues until the roller 323 rides up the cam 322 on dog 291 as the table approaches the last cam on the shaft. A spring 340 (Fig. 2) connected between the lever 321 and a stud 34! on the valve casing. 3I0serves to return the valve stem 323 to its normal position. so as to uncover the pipe 335 and allows fluid to exhaust from the cylinder chamber I50 through pipe 335, valve chamber- 339, pipe 342 and pipe 320 into the reservoir, thus allowing the spring I44 to start the wheel spindle reciprocation ready for finish grinding the first cam on the return stroke. At the same time, the V-port 3I9 is uncovered and unrestricted exhaust of fluid from the cylinder 250 starts the table 54 at its normal traversing or indexing speed.

Main control cam and valve Inasmuch as most of the mechanisms of the machine are controlled by fluid pressure mechanisms, there is provided a main control valve which is so controlled as to admit fluid under pressure-successively to the various mechanisms of the machine to produce the desired cycle of movement. As illustrated in the drawings, a main control valve 345 having-a valve stem 343 is arranged to control the movement of a hollow valve member having pistons 341, 343, 349, 350, 35I, 352 and 353. Fluid under pressure from pump I99 passes through pipe 200 into a valve chamber 354 in the main control valve 345. From this chamber, fluid under pressure passes through the pipe 331 into the chamber 333 in the slow speed or throttle valve 310. Fluid under pressure from the chamber 354 also passes through a central aperture 355 extending longitudinally within the movable main control valve. Fluid from the passage 355 enters the valve chamber 353 and passes out through the pipe 251 into the valve chamber 253 of the traverse or table index control valve. At the same time, fluid under pressure passing through the central aperture 355 passes into a valve chamber 351 and out through pipe 353 into a valve chamber 359 in the feed control valve I90. Fluid under pressure entering the chamber 359 serves to move the feed control valve in a direction toward the right to uncover the pipe 202 so as to cause a rearward feeding movement of the rinding wheel.

Main control cam In order that the mechanisms may function in proper sequence,- there is provided a suitable mechanism for actuating the main control valve 345. In the preferred construction, this mechanism comprises a main control cam 335 which is mounted on the end of a shaft 363 which is journalled in the base of the machine. The shaft 336 may be driven in any suitable manner.

Referring to Fig. 7, the main control cam is arranged to transmit its motion to a follower lower roller 318 always in engagement with the master or main control cam 335 so that as the cam rotates, the roller will follow the shape of the cam and transmit a corresponding movement to the valve stem 343. a

The cam 335 is preferably so shaped that one rotation of the cam moves the maincontrol valve stem 343 through one cycle to operate the various mechanisms of the machine so as to grind one cam and then index the work supporting table to position the next cam in operative relation with the grinding wheel; The table indexing or traversing movement which moves the work supporting table to position the next cam blank inoperative relation to the grinding wheel is accomplished by the nose or igh point of the cam. On various camshafts. the spacing between the cams varies somewhat and in order to compensate for the varying distance between cams, it is desirable that the noses of the cams be adjustable so that the mechanism may be set for the desired traversing movement of the table without loss of time, as in case a fixed cam were utilized. This is accomplished by providing a secondary cam 333 which is supported on a hub 331 on the cam 335. The cam 336 is connected to the cam member 335 by means of screws 333 which pass through arcuate slots 339 in the cam 333 and are screw threaded into the cam 335. -By. adjusting the cam 386 relative to the cam 365, the nose of the cam 366 may be adjusted so that it coincides with the nose 362 of the cam 365 or may be rotated so that it increases the effective length of the nose so that the indexing time between grinding successive cams may be varied as desired.

Mechanical feed of grinding wheel during tr'uing After the last cam on the shaft has been rough ground, the grinding wheel is moved to 50 this truing movement, it is desirable that the these features.

grinding wheel be advanced so that a suillcient amount may be trued off to maintain the wheel face in the same relative position with relation to the mechanisms of the 'machine. This is preferably accomplished by a pawl and ratchet mechanism, such as shown in 1. A ratchet wheel 424 is fixedly connected to the hand wheel I61. A pawl 425 is carried by a rock arm 426 which-is freely rotatable on the ratchet wheel hub. The lower end of the rock arm 426 is connected to a link 428 by a pin 426. The other end of the link 428 is connected by a pin 436 to a short link 43I which is carried on a stud 432. An arrow point member 433 is fixed on the stud 432 and is engaged by a cam surface 434 on a wheel feeding dog 435. The downward movement of the arrow point 433 rocks the links 43I and 428 and the arm 426 to actuate the pawl 425 and turn ratchet wheel 424 to cause an infeeding movement of the grinding wheel. A stop screw 436 is provided on the arm 426 to limit the movement of the rock arm in a counter-clockwise direction and a spring- 431 serves normally to maintain the rock arm 436.

in engagement with a fixed abutment 438. The extent of movement of the ratchet pawl 425, and consequently the extent of feeding movement of the grinding wheel may be varied by adjustment of the screw 436.

The machine and mechanism so far described will be found further described in the Letters Patent 2,022,178 hereinbefore referred to. According to the present invention the truing apparatus of the general type hereinbefore disclosed may be used together with the spindle reciprocating mechanism hereinbefore described and a single size of mastercams 66 may be utilized and the product camshaft may move on the table para lel to itsaxis, as is usual. Nevertheless taper cams can be ground retaining all The cross slide and work head.

'5I and the wheel head Ia. The line of division is preferably a horizontal plane, as indicated in these figures. 'I provide a cylindrical recess 566 in the wheel head 5Ia, in which fits a cylindrical block 56I having a large countersunk bore 562 in the upper part thereof. A conically headed bolt 563 seats in the bore 562 and extends through the.

The work table 54 is then wheel slide 5|. The bolt 563 has a threaded end 564 upon which are located a pair of 'nuts 565, a washer 566, and a heavy spring 561. The wheel head -5Ia is thus trunnioned on the-slide 5| and lostmotion is substantially eliminated. The block 56I may be secured to the wheel head 5Ia by means of screws 5l6.

Referring now to Figure 2 and also Figure 7; I provide under and attached to the cylinder I46 avalve casing 5I5. I provide a piston rod 5l6 which may be attached to the. piston rod I48 and is substantially a continuation thereof. A bore 5" extend up the piston rod 5l6 and is plugged at the lower end by a plug 5I8.. Four integral pistons 526, 52I, 522 and 523 are formed on the piston rod 5I6. Thereis an opening 524 into the bore 5 I I between the pistons MI and 522. There is an opening 525 at the upper side of the piston 526 and an opening 526 at the lower side of the piston 523, both extending into the bore 5". Central chamber 529 is thus connected to end chambers 521 and 528. Chambers 521 and 528 are connected by piping 536 to the main pressure line 266. Chambers 533 and 534, which are on the outside of chamber 529, are con nected by piping 535 to the exhaust line 2. Ports 546 and 54I are connected by piping 542 and 543 to the right-hand and left-hand sides, respectively, of a cylinder 545 (see Figure '6). In the cylinder 545 is a piston 546. Bothpiston and cylinder are of relatively large diameter. The cylinder 545 is rigidly fastened to the back of the wheel head 5Ia.- The piston rod 541 is connected to a. connecting rod 548 which in turn is connected to a bracket 54!! fastened by bolts 556 tothe cross slide 5|.

When the slow down cam 322 strikes the roller rod 5l6 are depressed. This occurs whenever dressing of the wheel is about to take place. This opens up the pressure fluid to the pipe 543 leading to the left-hand side of the cylinder 545,

moving the cylinder 545 to the left and (relatively) the piston 546 to the right, thus shifting the back of the wheel slide to the left and, therefore, moving the cross slide 5Ia angularly upon the wheel slide 5I. Subsequent to the dressing operation the spring I44 moves the piston rod 5l6 upwardly, admitting fluid to the piping 542 and, therefore, to the right-hand of the cylinder 545, moving the .wheel head angularly back to its original position.

I provide a pair of lugs 566 and 56I integral with the back of the wheel head 5Ia, through which extend bolts 562 and 563, the bolt.562 being in a position to engage the bracket 549 and the bolt 563 being in a position to engage a bracket 564 bolted by bolts 565 to the cross slide 5|. Adjustment nuts 566 and 561 are provided for adjusting the bolts 562 and 563, the lugs 566 and 56I being internally threaded. These. constitute adjustable stops to limit the relative movement of the parts in either direction.

. I prefer that the wheel be trued to a truly cylindrical shape and, therefore, adjustmens aremade so'that durin truing, the spindle of the grinding wheel is parallel to the axis of the work piece. This produces a truly cylindrical grinding wheel and, therefore, in the subsequent grinding operation, the wheel spindle may reciprocate withoutany interference. By simply reversing the pipe connections 542 and 543, I can change the direction of taper upon the product camshafts. For the grinding of automotive camshaits, the desired taper is not great, being of the order of from three to ten minutes of arc. This is so small that no attempt has been made to illustrate the angular displacement of the parts in the elevation drawings.

The angular movement of the wheel head is synchronized with the dressing apparatus so that whenever the wheel is to be dressed, the wheel head is first shifted angularly and before grinding is resumed, the wheel head is shifted back again. By using fluid pressure to shift the wheel head, a powerful force may be exerted which will positively move the wheel head to the desired angular position and maintain accuracy in the grinding and truing operations.

It will thus be seen that there has been provided by this invention apparatus in' which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embcdiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as-illustrative and not in a limiting sense.

I claim:

1. In a grinding machine, a carriage mounted on ways, a cross slide mounted on ways to move transverse to the motion of said carriage, a. work holder, a grinding wheel head mounted on one of said parts, a spindle in said wheel head, a

grinding wheel on said spindle, a dressing devicerositioned so that movement of the carriage causes relative movement between the dressing device and the grinding wheel, a pivotal mounting for the grinding wheel head perpendicular tothe spindle means to move the carriage for dressing, and means actuated by and in timed relation with said carriage movement automatically to shift the wheel head on the pivotal mounting whereby to grind a plurality of tapers'for a given adjustment of the cross slide.

2. In a grinding machine, a base, a work table or carriage mounted on said base for rectilinear movement thereon, a dressing diamond mounted on said table or carriage, a cross slide mounted on said base for rectilinear movement perpendicular to the first named movement, a wheel head mounted onsaid wheel slide for angular movement, a grinding wheel journalled in said wheel head, and powermeans actuated in timed relation with said table movement automatically to shift the wheel head angularly whereby to grind a work piece with the wheel head at one angular position and to dress the grindingwwheel with the wheelhead at another angular position.

3. In a cam grinding machine, a wheel slide, a work table and a rock bar thereon, each of which is operated by a separate fluid motor, a m'ain control valve in control of said motors, a swivel support for said wheel slide, a fluid motor in control thereof, and means including a valve actuated by and in timed relation with said table to control said wheel slide swivel motor.

4. In a cam grinding machine, a rotatable grinding wheel, a transversely movable wheel slide therefor, a longitudinally movable work' table, and a rock bar thereon, a swivel support for said wheel slide, each of which is operated by a separate fluid motor, a main control valve in control of saidwheel slide and work table and rock bar motors, and means including a control valve actuated by said table to control the wheel slide swivel motor.

5. In a cam grinding machine having a rotatable grinding wheel, a wheel slide therefor, a work table and a rock bar thereon, a swivel support for said wheel slide, each of which is operated by a separate fluid motor, a main control valve in control of the wheel slide and work table and rock bar motors, a slow speed valve, means actuated by said table to operate the slow speed valve to cause a slow traversing movement of said table, and means including a valve which is actuated in timed relation with said slow speed valve automatically to control said swivel motor to position the wheel slide for a truing operation.

6. In a cam grinding machine having a rotatable grinding wheel, a wheel slide therefor, a work able and a rock bartthereon, a swivel support forv said wheel slide which is arranged to position said grinding wheel with its axis either parallel to or at an angle relative to said work table, each of which is operated by a separate fluid motor,

a main controlvalve in control of said wheel slide and work table and rock bar motors, a truing tool on said table, and means including a valve actuated by said table automatically to control said swivel motor to position the grinding wheel with its axis parallel to said table for a truing operation and at an angle relative thereto for a grinding operation.

"I. In a grinding machine, a work table, a fluid pressure motor for traversing said work table, a cross slide, means for moving said cross slide transversely to the direction of motion of the table, a grinding wheel head, a swivel support for said grinding wheel head on said cross slide, a fluid motor connected to move said grinding wheel head on said swivel support, and means including a valve actuated by and in timed relation, with said table to control the angular position of said grinding wheel head on said cross slide and swivel support.

CERTIFICATE or CORRECTION. Patent-No. 2,135,337. January 2, 191m.

cEimcE cnonrzron, JR.

' It is hereby certified that error appears in theprinted specification of'the ebove mmb'ere'd patent requiring correction as follows: Page 8, sec- 0nd column, line 55, claim 6, for the word "able" rec'd --tebleand that I the said Letters Patent should be read with this correctionitherein that the some mey conform to the record of the case in the Patent Office.

Signed and sealed this 15th day-of October, A. D. 19140.

, "HenryV an Arsdele, v (Seei) Acting domiesioner of Patents} 

